Forty years of hard work to perfect it: How China developed its own complete set of aromatic hydrocarbon technologies

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How were the “milestones” in the petrochemical industry achieved? In China’s petrochemical sector, there is a technology that reflects the level of the country’s equipment manufacturing industry – namely, the set of aromatic compounds production technologies developed over four decades by Chinese petrochemical scientists, technologies for which independent intellectual property rights exist. This technology has recently caught the interest of a renowned international oil company, and it is set to go global, becoming highly sought-after in the context of overseas expansion and the Belt and Road Initiative. After forty years of development, aromatic hydrocarbons, including toluene and para-xylene (PX), are important basic chemical raw materials. Every aspect of our daily lives (clothing, food, shelter, transportation) relies on its contributions; for example, the clothes we wear, the cars we drive, the packaging for food, medicines, and beverages, as well as various plastics we use – all are related to aromatic hydrocarbons. Wu Wei, deputy chief engineer at the Sinopec Research Institute of Petroleum and Petrochemicals, told a reporter from China Science Daily that the basic raw materials for the petroleum and petrochemical industry fall into two main categories: olefins and aromatics. There are a great variety of aromatic derivative products; among the more than 8 million known organic compounds, aromatic compounds account for about 30%. Aromatic hydrocarbon technology packages are high-end technologies that are characterized by their complexity and high technical demands; they represent a key indicator of the level of development in the petrochemical industry. Previously, only two renowned foreign companies worldwide possessed the complete technology for aromatics, creating a de facto monopoly on this technology market. According to Wu Wei, aromatic hydrocarbon production technologies have high technical barriers due to their high level of system integration and the difficulty involved in their development. The costs associated with technology licensing, as well as specialized adsorbents and catalysts, are also extremely high. In 1975, China imported the technology for a PX plant with an annual production capacity of 27,000 tons, at a cost of several million dollars ； In 2007, the technical costs alone for a 600,000 tons per year PX plant amounted to tens of millions of dollars. Kong Dejin, deputy chief engineer at the Sinopec Shanghai Research Institute of Petrochemical Technology, explained that in order to overcome the core challenges related to aromatics technology, generations of professionals from the petrochemical industry, universities, and research institutions have worked for over 40 years since the 1970s, and as a result China has become the third country after the United States and France to possess complete technologies related to aromatics. Our country holds the intellectual property rights for all the technologies involved in this project, with over a hundred authorized patents both domestically and internationally. Six academicians, including Min Enze, gave high praise to this project, stating that the successful development of the aromatic hydrocarbons technology package represents a \"milestone\" in petrochemical technology. This project has achieved numerous significant innovations and breakthroughs in areas such as processes, engineering equipment, control methods and systems, as well as adsorption materials and catalytic materials. It is at the international leading level overall and holds great value for promotion and application. To overcome the last remaining challenge, Hong Dingyi, an executive director of the Chinese Chemical Society, believes that the success in transitioning aromatic hydrocarbon production technologies – which are characterized by high complexity, high investment costs, and high risks – from the laboratory stage to industrial application in China is largely due to strategic support at the highest levels, close collaboration between industry, academia, and research institutions, as well as the advantages of highly integrated efforts in research, design, construction, and production within China’s petrochemical sector. Since the 1970s, institutions such as the Sinopec Research Institute of Petroleum Chemistry and the Shanghai Petrochemical Research Institute have successively developed production technologies for aromatic units, including aromatic extraction, xylene isomerization, toluene disproportionation, and alkylation. However, the PX adsorption separation technology has yet to be overcome, remaining the last stronghold of the aromatic hydrocarbons technology suite. Due to this shortcoming, our country is forced to import millions of tons of PX products each year, spending nearly $10 billion in foreign exchange. Wu Wei told reporters that in order to break the monopoly of foreign adsorption and separation technologies, Sinopec began researching PX adsorption and separation technologies in the early 1990s. It developed the domestically produced adsorbent RAX-2000A, which was tested on an industrial scale at the Qilu branch in 2004; all its performance indicators met or exceeded those of imported adsorbents, and its price was one-third lower than that of imported ones at the time. In 2009, in order to break the monopoly of foreign companies on PX adsorption and separation technology, Sinopec established a leadership team for advancing aromatic hydrocarbon technology, headed by Senior Vice President Dai Houliang. This team was tasked with tackling the last remaining challenge in aromatic hydrocarbon technology – PX adsorption and separation technology – in order to complete the development of this entire technology set; they were determined to overcome this difficult obstacle at all costs. In the same year, PX adsorption separation technology was included in Sinopec’s “Ten Key Projects” initiative, marking the official start of efforts to develop independent PX adsorption separation processes. In 2011, Sinopec utilized its independently developed PX adsorption separation technology to build the first industrial plant with an annual capacity of 30,000 tons at Yangzi Petrochemical, employing the newly developed RAX-3000 type domestic adsorbent, thereby verifying the reliability of its own PX adsorption separation technology. Since then, Sinopec has successfully overcome the last hurdle in its independent aromatic hydrocarbon production technology—the adsorption separation technology—and acquired the complete set of technologies for aromatic hydrocarbon production. Relying on its independently developed aromatic compound technology, Sinopec built another large-scale aromatic compound complex at Hainan Refining & Chemical Plant with an annual PX production capacity of 600,000 tons. It was successfully commissioned on December 27, 2013, after a single successful start-up. Hong Dingyi, the innovator behind the triple jump, told reporters that over the past 40 years, China’s aromatics technology has gone through three stages: following others, moving in parallel with others, and leading through innovation. PX technology is the core component of the aromatic hydrocarbons technology package. Taking the development of adsorption separation processes as an example, Wu Wei explained that PX separation technology employs a simulated moving bed adsorption separation process, which integrates adsorbents, specialized equipment, relevant processes, and dedicated control systems. The overall process is complex, making it extremely difficult to develop such technologies. PX products require a high level of purity, with a minimum of over 99.7% ； The characteristic of simulated moving bed technology is that the apparatus features a complex network of process pipelines, which need to cycle through various materials such as raw materials and products that differ greatly in composition. Residues of these materials within the pipelines can cause contamination of the products. Even trace amounts of residual other materials, if not removed, will affect the purity and yield of the product. In order to overcome the technical challenges as quickly as possible, researchers gave up their holidays and weekend breaks, working tirelessly day and night on experiments. They developed a simulated moving bed technology with independent intellectual property rights, overcame the control problems associated with the adsorption process control system (MCS), and creatively devised a pipeline flushing process for the adsorption chamber bed layer that differs from similar international technologies. They also designed specialized components that met the requirements of the process, thereby fully resolving all the technical challenges involved in the PX adsorption separation process. Furthermore, during the research and development process, scientists also focused on emphasizing the concepts of greenness and low carbon emissions. Compared with similar domestic plants, Hainan Refining and Chemical’s PX plant consumes 25% less energy per ton of PX produced, which translates into savings of hundreds of millions of yuan annually in terms of energy reduction. In addition, researchers were the first to use the low-temperature heat energy from the top of the recovery tower to generate electricity, enabling the combined facility to produce more electricity than it consumed overall. This achieved a historic breakthrough, allowing the facility to supply 65,000 kWh of electricity per day. As a result, Hainan Refining and Chemical’s PX unit has become the new global benchmark for aromatic compound production units, thanks to its lowest energy consumption. Understanding one’s own foundation: Currently, the global annual consumption of aromatics for industrial use is around 120 million tons. There are more than 130 aromatics production plants, located in developed countries and regions such as the United States, Western Europe, Japan, and South Korea. PX is the aromatic compound with the highest consumption and the most representative production technology; it features a diverse range of downstream industries and serves as a fundamental component of the petrochemical industry. Wu Wei told reporters that with the continuous development of China’s economy and the increasing needs of its people, China’s consumption of PX has grown rapidly, with an average annual growth rate of over 20% in the past 15 years. To date, our country has become the world’s largest consumer of PX, but it has long suffered from a shortage of domestic supply and has relied on imports. In 2014, approximately 10 million tons were imported, accounting for about half of total consumption, of which 75% came from developed countries such as the United States, Japan, and South Korea. While domestic citizens protest against the development of the PX industry, the United States, Japan, and South Korea are all building new PX plants for the Chinese market. In response to public concerns regarding PX, Lu Dapeng, the spokesperson for Sinopec, believes that it is necessary to present facts and reasons from a scientific perspective, as well as to analyze the root causes of the problem from a political standpoint, so that the public understands that the aromatics industry, which is crucial to the country’s economy and people’s livelihoods, must remain under Chinese control and not be subject to external influence. Furthermore, in response to the societal panic stemming from the demonization of PX, and to ensure green and safe production, Hainan Refining & Chemical has made \"zero pollution, zero leaks, zero emissions, and intrinsic safety\" key objectives from the outset of the project’s development, aiming to achieve \"no emissions in the air, no leaks on the surface, and no seepage underground.\" To ensure the intrinsical safety of its facilities, Hainan Refining has invested over 20% in safety and environmental protection. The SO2 content in the flue gas is as low as 20 mg/Nm3, which is far below the standards for Category 1 emissions and represents an advanced level on a global scale. Additionally, the emission of carbon dioxide, a greenhouse gas, is reduced by 12,000 tons per year, exceeding even the international advanced levels. Furthermore, in the raw material purification unit, catalytic reactions have been innovatively used in place of physical adsorption, which significantly extends the lifespan of the catalysts and reduces solid waste emissions by 98%. In Hong Dingyi’s view, thanks to the complete intellectual property rights, advanced standards, and a commitment to continuous improvement associated with China’s aromatics technology, \"we can promote our aromatics technology globally, just as we have promoted China’s high-speed rail technology.\" ”As China’s own aromatic hydrocarbon technologies make their way onto the global stage and enable it to gain control over pricing, this is of great significance for driving the rapid development of related manufacturing industries and downstream sectors, as well as for improving the quality and efficiency of China’s economic development and accelerating structural transformation.